91058770 ÷ 13 
The aim is to understand the frequency of 13 in 91058770.

Going ahead to step 1:
If we divide 9 by 13, we get 0 and a remainder of 9.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 9 after subtracting 0 from 9.
Append the next digit (1) from the dividend to 9 and continue with: 91 / 13

Step 2:
91 divided by 13 is 7 with a remainder of 0.
Use 7 as the next digit of our solution. 
Result so far: 7.0
Deduct 91 from 91 and we're left with 0.
Bring next digit (0) of the dividend behind the 0 and repeat the process: 0 / 13

On to step 3:
When dividing 0 by 13, we get 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 70.0
Subtract 0 from 0 to get 0.
Append the next digit (5) from the dividend to 0 and continue with: 5 / 13

Let's proceed to step 4:
When dividing 5 by 13, we get 0 with a remainder of 5.
Put 0 as the next digit of the answer. 
Result so far: 700.0
Subtract 0 from 5 to get 5.
Grab the next digit (8) from the dividend, add it to 5, then carry on: 58 / 13

Advancing to step 5:
58 divided by 13 is 4 with a remainder of 6.
The number 4 becomes the next digit in our result. 
Result so far: 7004.0
Deduct 52 from 58 and we're left with 6.
Grab the next digit (7) from the dividend, add it to 6, then carry on: 67 / 13

Moving on to step 6:
If we divide 67 by 13, we get 5 and a remainder of 2.
Record the quotient 5 as the next digit in the result. 
Result so far: 70045.0
If we take 65 away from 67, we end up with 2.
Fetch the next digit (7) from the dividend, attach it to 2 and continue: 27 / 13

On to step 7:
When dividing 27 by 13, we get 2 with a remainder of 1.
The number 2 becomes the next digit in our result. 
Result so far: 700452.0
The remainder is 1 after subtracting 26 from 27.
Append the next digit (0) from the dividend to 1 and continue with: 10 / 13

Moving on to step 8:
If we divide 10 by 13, we get 0 and a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 7004520.0
Subtracting 0 from 10 leaves us with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 9:
13 can be fit into 100 7 times, resulting in a remainder of 9.
Write down 7 as next digit of the result. 
Result so far: 7004520.7
The remainder is 9 after subtracting 91 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Moving on to step 10:
90 divided by 13 is 6 with a remainder of 12.
The number 6 becomes the next digit in our result. 
Result so far: 7004520.76
If we subtract 78 from 90, we get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Going ahead to step 11:
13 goes into 120 9 times with a remainder of 3.
The next digit of our result is 9. 
Result so far: 7004520.769
Subtract 117 from 120 to get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Step 12:
30 divided by 13 is 2 with a remainder of 4.
The next digit of our result is 2. 
Result so far: 7004520.7692
If we subtract 26 from 30, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 13:
40 divided by 13 is 3 with a remainder of 1.
Put 3 as the next digit of the answer. 
Result so far: 7004520.76923
Subtracting 39 from 40 leaves us with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Moving on to step 14:
When dividing 10 by 13, we get 0 with a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 7004520.76923
Deduct 0 from 10 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 15:
13 can be fit into 100 7 times, resulting in a remainder of 9.
The number 7 becomes the next digit in our result. 
Result so far: 7004520.7692307
If we take 91 away from 100, we end up with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Step 16:
If we divide 90 by 13, we get 6 and a remainder of 12.
The number 6 becomes the next digit in our result. 
Result so far: 7004520.76923076
Subtract 78 from 90 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

The final outcome is 7004520.76923076, with a leftover of 1.2e-08.